Modeling the Mechanical Behavior of a Natural Polymeric Composite Material Using Micromechanical Models

This doctoral thesis project addresses the challenge of sustainability by developing high-performance composite materials from renewable natural resources, specifically using Guadua Angustifolia Kunth (GAK) bamboo fibers to reinforce a polypropylene matrix. The main problem lies in the difficulty of applying existing micromechanical models, developed for inorganic reinforcements, to natural fibers due to their high morphological and mechanical variability (non-cylindrical, variable modulus, heterogeneous distribution). The objective is to predict the elastic modulus and tensile strength of the injection-molded composite using an analytical micromechanical model. This model will be tuned to determine the reinforcement efficiency factor ($\xi$), incorporating the effects of fiber length distribution and orientation. Furthermore, the Interfacial Shear Stress (IFSS) will be estimated using macromechanical testing and models such as Kelly–Tyson and Bowyer–Bader. The methodology involves morphological and rheological characterization of the fiber and composite, development of the predictive algorithm, numerical validation, and simulation of the injection process, culminating in the laboratory-scale production of a commercial product using the new material.<br/><br/><b>Goal</b>: <br/>To model the mechanical behavior of a natural polymer composite material, specifically polypropylene reinforced with short bamboo fibers (GAK), using analytical micromechanical models to predict its elastic modulus and tensile strength, aiming for commercial application.<br/><br/><b>Research lines</b>: <br/>Simulation and modeling of composite materials